The invention relates to a method of clearing a target range or other area, such as a war zone, of buried unexploded ordnance (UXO).
The hazards of unexploded ordnance (bombs, artillary shells, rockets, fuzes, etc.) in a war zone are obvious and have to be dealt with in time to avoid risk to life and property. Less obvious are the hazards found in and around military training areas. To enable realistic combat training, live ordnance is necessary. As on the battlefield, a certain percentage of fuzing devices used with the ordnance fail to operate properly, leaving powerful explosive items which could self-initiate at any time due to environmental exposure and shock. The extent of ground penetration of ordnance items depends upon impact velocity, impact angle, weight, and the characteristics of the soil. Usually the heavier items penetrate to greater depths than the smaller items; however, they can be expected at any depth depending on impact and soil.
In time, such live impacted ranges become unfit for combat training due to the density of hazardous items. Eventually it may be desired to return the area to civil or other military use. But, often there are political considerations and it is not an option to merely declare an area "off-limits." The area must be cleared and rendered safe for alternate uses.
Established procedures for clearing areas of such ordnance involve in the main a physical undertaking employing personnel using tools and power machinery. This is both dangerous and expensive, ranging up to as much as $10,000 or more per acre. It is a slow process requiring considerable caution. Generally, a plot of land is marked off in grids and a crew is assigned to a specific grid to walk over it in over-lapping patterns for first clearing the surface. Thereafter, a few inches of the surface soil is removed by powered scrappers and the soil sifted for ordnance. Once this is completed, ordnance teams employ magnetometers and metal detectors to detect and remove ordnance pieces for the next twelve to eighteen inches in depth. The effectiveness of this method is limited, of course, by soil conditions and metal debris. While a magnetometer may detect a metal object in the ground, it can not readily distinguish, for example, shrapnel from ordnance.
It is to these problems that the present invention is directed as a safe and economical method, where time permits, of clearing a range or area of ordnance, some of which is unexploded and may be very unstable to shock or movement.